NEW YORK (Reuters Health) - For people with a simple sore throat or ear infection, a "retail" health clinic may treat the problem as well as, and more cheaply than, the family doctor, a study published Monday suggests.

The study, reported in the Annals of Internal Medicine, is the first to assess quality of care at U.S. retail health clinics, which operate mainly out of pharmacy chain stores, but also in grocery chains and "big box" stores like Wal-Mart.

Analyzing a year's worth of claims from patients in a large Minnesota health plan, researchers found that for cases of sore throat, ear infection and urinary tract infection (UTI), retail clinics and doctors' offices provided a comparable quality of care.

The difference was that retail clinics did so at a lower cost: the average visit cost $110, versus $166 at doctors' offices.

Retail clinics provide quick walk-in care for a limited number of health conditions, as well as certain health screenings, like cholesterol and blood pressure checks. Convenience and relatively low costs have made them increasingly popular, but the clinics have also come under criticism for a number of reasons.

Retail clinics are typically staffed by nurse practitioners, and some have questioned whether NPs are more likely than doctors to misdiagnose patients' problems. The clinics also lack records for their walk-in patients, which in theory could undermine people's overall healthcare.

"When you visit your primary care doctor, he or she can look at your record and see that you haven't had, for example, your routine Pap smear," said study leader Dr. Ateev Mehrotra, of the research organization RAND in Pittsburgh.

"When you go into a retail clinic," he told Reuters Health in an interview, "the nurse practitioner there doesn't know you didn't have your Pap smear."

But Mehrotra and his colleagues found no evidence that having a simple complaint treated at a retail clinic hurt patients' chances of receiving preventive care.

Of patients who had their sore throats, ear infections or UTIs treated at a retail clinic, 14 percent got a routine check-up or other preventive service within the next three months. That figure was the same among patients who had gone to a doctor for those problems.

The findings suggest that retail clinics are a reasonable option for simple health problems, Mehrotra said, and they also support past studies showing that NPs generally provide high-quality care.

One of the remaining questions about retail clinics, however, is whether they further fragment an already disjointed U.S. healthcare system, where a patient's different providers do not necessarily communicate well with each other.

To help guard against this, Mehrotra suggested that retail-clinic patients get a print-out of their visit summary and have the clinic fax the record to their primary care doctor.

He also recommended that people with serious chronic health conditions stick with seeing their primary care provider, even for minor complaints, since he or she will know their medical history.